1. Field of the Invention
This invention relates to shock absorbing apparatus suitable for use on load carrying vehicles such as lorries, coaches, buses and trains and to vehicles equipped with such apparatus.
2. Description of Prior Art
It is known to provide load carrying vehicles with shock absorbing apparatus such as bumper bars at the front and rear at a specific height so that when vehicles in line one behind the other bump into each other, the bumper bars absorb the shock of impact and shock absorbing means may be incorporated to assist in such shock absorption.
A difficulty sometimes encountered with such shock absorbing devices is that they are sufficiently close to the ground at their lowest point to be damaged on uneven ground surfaces and when driving the vehicles onto the ramps of roll-on roll-off ferries. To be effective it has been found that the shock absorbing apparatus must be constructed so that there is not more than about 18 to 20 inches from the underside of the bumper bar across the vehicle to the ground surface in the normal i.e. undeflected position. These requirements vary from country to country according to the requirements of national laws and local regulations. However with these dimensions there is the problem that when the vehicle rolls or is driven into or off a sloping ferry ramp the bumper bar is over the ramp while the vehicle wheels are on the adjacent ground and thus the bumper bar can engage the ramp surface. In such event the shock absorbing apparatus and/or ramp is damaged. Similar difficulties arise when the vehicle is driven over rough or undulating ground.
The main object of the present invention is to provide improved shock absorbing apparatus of this general type in which the aforesaid difficulties are minimised or eliminated.